Electrical fuse.



LE. WOOD.

ELECTRICAL FUSE. Avucmon FILED MAY21, 1913.

1 178, 99. 'Patented Apr. 4, 1916.

UNITED STATES PATENT OFFICE.

JOHN E. WOOD, 0F NEW YORK, N..Y., ASSIGNOR TO METROPOLITAN ELECTRIC MFG.

CO., A CORPORATION OF NEW JERSEY.

ELECTRICAL FUSE.v Y

Specification of Letters Patent.

Patented Apr. 4, 1916.

Application filed May 21, 1913. Serial No. 768,911.

-zen of the United States, residing at the city of NewYork, borough ofBrooklyn, and State of New York, have invented cer` tain new. andxuseful Improvements in Electrical Fuses, of which the following is afull, clear, and exact description.

This invention relates to inclosed 'fuses for electric circuits.

The object is to provide primar1ly for making. the terminals and thefuse elements into 'a mechanically distinct and independent unitarystructure from the inclosing casing. Such a construction affords manyadvantages which will be pointed out hereinafter.

The invention consists essentially in connecting the metallicterminalsvof an inclosed fuse mechanically together by means of a stoutbar of non-conducting material.

The invention also consists in certain details of construction relatingto the casing of the fuse and to means for connecting and disconnectingthe fuse element therewith.

In the accompanying drawing; Figure 1 is a plan of the unitary structurecomprising the inclosed fuse element; Fig. 2 is a side elevation of thesame; Fig. 3 is a view similar to Fig. 1, when associated with thecasing; Fig. 4 is an end View of the casing with parts broken away; andFig. 5 1s a section of one of the end caps of the casing.

The fuse element comprises essentially two terminal plates 1 and 2connected together by a bar 3 of non-conducting material and the fusiblestrip 4 through which the current passes from one terminal to the other.The bar 3 is permanently fixed to the two terminal plates 1 and 2 bymeans of rivets 5 or in any other suitable manner.

The bar is of sufficiently stout material and Y of such a size as tosustain all the strains to which the device will be subjected inhandling or use. The fusible strip 4 may be of any approved form and itis secured at its extremities tothe respective terminal plates l and 2by means of bolts 6 and nuts 7 instead of' by solder as is the usualpractice. Since the two terminal plates are permanently secured togetherby the bar 3 and the bolts 6 are permanently located at a definitedistance apart, the fusible strip can be-made of a standard shape andsize and be quickly adjusted and connected to the terminals by fuse inthe circuit.

means of the bolts and nuts referred to, and by this method ofmountingythe fuse, the latter is not liable to injury through lack ofsupport when being assembled and the bolts and nuts furnish perfectcontact between the fuse and the plates. This unitary structure is to beinclosed in a suitable caslng which is of the ordinary tubular formindicated in the drawing by 8. This tube surrounds the adjacent ends ofthe terminal plates and the fuse element and connecting bar, the outerends of the terminals 1 and 2 projecting through and beyond the ends ofthe tube to afford means for connecting the Each end of the tube isprovided with a metal cap 9 havingl a narrow fiange 10 extendinglaterally inward and which holds in place a loose metal disk 11, theedges of the same being clamped between the flange 10 and the end of thetube. This disk is provided with a number of perforations 12 to affordventilation to the in-v terior of the casing andit is also provided witha diametrical slot 13 extending nearly but not quite across it. Thisslot is of such dimensions as to just'allow one of the terminal platesto pass through it. The flange l() of the cap is provided at oppositepoints with notches 14.- of such size as to nicely fit the edges of theterminals 1 and 2 and the depth is such, as to permit the terminal whenlined up with the two notches, to pass through them. The flange 10adjacent one side of each notch 11 is deeper than at other places andformed with an eccentric surface 15. This portion being likewisebent'outward or away from vthe disk 11 as shown in Fig. 5. Theterminalplates 1 and 2 are each provided with oppositely disposed notches 16which are adapted to receive the edge of flange 10 on the cap.

To assemble the unitary fuse structure in the casing, the disk 11 andcap 9 are first applied to one end of the tube 8, then the fusestructure is passed through the opposite end of the tube and the plate 1is directed through the slot 13 in the disk after which by twisting theunitary structure and rotating the' disk. the plate 1 is brought intoalinement with the notches 14 through which then the plate readilypasses. The Aplate is slipped through until its notches 16 come into theplane of the flange 10 whereupon the unitary structure is rotated a halfturn, which brings the inclined surfaces on the flange against thebottom of the notches 16 and causes a frictional engagement therewith,which prevents the cap and plate from rotating in either directionfarther with respect to each other. The other cap and disk are thenslipped over the endof the other terminal plate until the notches 16 inthe plate are in the plane With the flange 10, when the cap is rotatedto bring the eccentric surfaces 15 into the notches 16. At the instantof the engagement by ythe surfaces 15, the faces of these parts of theflange which project outward, engage the ends of notch 16, which causesone cap to be drawn along the tube toward the other and holds all of theparts together by friction.

To disassemble the structure in order to refill the fuse, the unitarystructure is simply rotated in the opposite direction through a halfturn to bring the notches of one of the terminal plates into line withnotches, 14, whereupon the unitary structure can be bodily Withdraivnfrom the tube. When thus withdrawn, it will be seen that the process ofremoving the ends of the destroyed fuse and substituting a good fuseca'n be easily and quickly accomplished, because of the fact that thetwo terminals are firmly secured together.

The structure as a Whole, has great mechanical strength on account ofthe reinforcing bar 3 and the strain of handling the device either inapplying it to the contacts with which it is to be associated, or inremovi g it therefrom is sustained by the unitary structure and not bythe tubular casing. For this reason the casing may be of lighter andless expensive material than usual and may be even made of iexible andireproof material should those qualities be desired. The fuse elementcan be easily examined or handled at any time Without getting it out -ofadjustme'ritor getting the contacts out of alinement and'thusintroducing difliculty in replacing the element in the casing.

It is to be understood of course, that the interior of the casing is tobe filled as usual with non-conducting material in commi either arefllable or non-refillable inclosedl fuse, but its advantages are bestobtained in the refillable type.

Having described my invention, I claim:

1. In an inclosed fuse, a tubular casing open at both ends, flanged capsttinglexteriorly over the ends of said casing, closing `disks interposedbetween the flanges of said caps and the ends of said casing, a unitaryfuse structure contained in said casing and projecting through slots insaid disks, means on said structure and flanges of said caps,respectively, for drawing'the caps toward each other upon relativerotation thereof and for locking said caps in position.v

2. In an inclosed fuse, the combination with a tubular casing, theflanged caps and closing disks, said disks having slots'and the flangeshaving oppositely disposed notches, a unitary fuse structure containedin said tube and projecting through the slots in said disks, saidstructure having notches adapted to embrace the flanges of the caps andmeans for limiting the relativerotation of the caps and unitarystructure.

In Witness whereof, I subscribe my signature, in the presence of' twowitnesses.

JOHN E. WOOD. Witnesses: WALDo M. CHAPIN, REUBEN LOUER.

